For me, there's 2 main reasons I prefer retail over digital
1: More freedom with the game. I can lend it to a friend or sell it used. Much more convenient than the way to lend digital games (Create account on friend's console, then download the whole game, then delete it if someone else wants to play it on another console. For handhelds, it's not possible at all, as they only have 1 account)
2: They generally cost less. A $60 game on PSN or Xbox Live is going to stay at $60 indefinitely, only dropping temporarily during occasional sales. Disc-based games often start dropping in price as little as a week after launch. I buy my retail games from Amazon (no sales tax) So even at launch, I'm paying exactly the same as for a digital game, plus get the benefits as listed above.
Only way to make me go all-digital is to make digital games cost less than their disc-based counterparts.
"Never argue with stupid people. They will drag you down to their level and then beat you with experience."
-Samuel Clemens
